fix: default unset signing transport to local (#3309)

`/api/health` and `/api/certificate-status` reported the cert as
available when `NEXT_PRIVATE_SIGNING_TRANSPORT` was unset, even though
sealing defaults to the local P12 and fails if it is missing,
unreadable, or expired.

apps/remix/app/routes/api+/certificate-status.ts

@@ -1,8 +1,8 @@
 import { getCertificateStatus } from '@documenso/lib/server-only/cert/cert-status';
 
-export const loader = () => {
+export const loader = async () => {
   try {
-    const certStatus = getCertificateStatus();
+    const certStatus = await getCertificateStatus();
 
     return Response.json({
       isAvailable: certStatus.isAvailable,

apps/remix/app/routes/api+/health.ts

@@ -22,7 +22,7 @@ export const loader = async () => {
   }
 
   try {
-    const certStatus = getCertificateStatus();
+    const certStatus = await getCertificateStatus();
 
     if (certStatus.isAvailable) {
       checks.certificate = { status: 'ok' };